int main(int argc, char *argv[])
{
int opt;
int reverse = 0;
int fold = 0;
int total = -1;
char *lines[MAXLINES];
while ((opt = getopt(argc, argv, "rhf")) != -1) {
switch (opt) {
case 'r':
reverse = 1;
break;
case 'f':
fold = 1;
break;
case 'h':
usage(argv[0]);
break;
default:
fprintf(stderr, "unknow opt: %c\n", opt);
break;
}
}
if ((total = readlines(lines, MAXLINES)) >= 0) {
if (fold) {
qsort_c(lines, 0, total, charcmp);
} else {
qsort_c(lines, 0, total, strcmp);
}
writelines(lines, total + 1, reverse);
}
exit(0);
}
// recursive Qsort--------------------------------(not used)
void qsort_c(float *array,int l,int r,int *index) {
int j;
if ( l < r ) {
// divide and conquer
j = partition( array, l, r,index);
// j=(l+r)/2;
qsort_c( array, l, j-1,index);
qsort_c( array, j+1, r,index);
}
}
void qsort_c(char *v[], int left, int right,
int (*comp)(void *, void *))
{
int i;
int last;
if (left >= right)
return ;
swap(v, left, (left + right) / 2);
last = left;
for (i = left + 1; i <= right; i++)
if (comp(v[i], v[left]) < 0)
swap(v, ++last, i);
swap(v, left, last);
qsort_c(v, left, last - 1, comp);
qsort_c(v, last + 1, right, comp);
}
